The subject of the present invention is, particularly, lances used for the conversion of cast iron into steel and which are dipped into the converter in order to inject the refining substances into the metal bath. For this purpose, these lances comprise a series of channels, generally concentric, for blowing in these substances and for cooling the lance.
U.S. Pat. No. 3,972,515 the disclosure of which is incorporated herein by reference, proposes a device for coupling such a lance leaktightly to a manifold which is in communication with the ducts supplying the lance with refining substances and with cooling liquid. The contact surfaces between the lance and the manifold must, of course, be designed as a leaktight surface in order to prevent any leakage of these gaseous and liquid substances, while the clamping between the manifold and the lance must be sufficiently powerful to preserve this leaktightness.
In the device known from the abovementioned document, the mounting of the lance on the manifold is effected manually with the aid of clamping bolts. In the device proposed in the document DE-Al-3,828,928, the mounting of the lance on the manifold is effected automatically via pivoting hooks actuated by hydraulic jacks.
In both of the two devices, the mounting between the lance and the manifold must not only ensure leaktightness at the joining surfaces, but also the support of the lance, given that the latter is carried by the manifold. If follows that a very rigid mounting is necessarily required between the lance and the manifold with the consequence that the manifold, the joint and the ducts are obligatorily exposed to the vibrations of the lance.